The present invention relates generally to a lock device and lock method for a valve, such as a knife gate valve. More particularly, the invention relates to a lock device and method that can lock the valve in a position such as an open and/or closed position.
Various valves are known, including knife gate valves, which may have a knife gate element that reciprocates between open and closed positions. The knife generally moves in a reciprocating linear manner across the area of the fluid channel to form a gate by being actuated by an actuator such as a hydraulic or pneumatic actuator.
There is a need in the art for a simple, convenient, inexpensive device and method to lock the valve in the open and/or closed positions. For example, it may be desired to be able to lock the valve in an open position to avoid problems that might occur should the valve accidentally be activated to close at an improper time, such as during repair. Without a lock, the accidental closing of the valve could cause damage to a partially disassembled valve, or to parts located in the path of travel of the gate of the valve. Also, accidental opening or closing of a valve due to a control failure could damage other machinery associated with the flow system with which the valve is associated.
The present invention provides a device and method for locking a knife gate valve in a position, such as an open and/or closed position. The invention can provide benefits such as preventing accidental opening or closing of the valve. In one aspect, the invention provides a locking device for a knife gate valve having a housing and a reciprocating shaft that reciprocates a knife in back and forth directions. The locking device has a pair of first posts disposed substantially parallel to the shaft, each first post having one end mounted to the housing, and each first post having a first engageable portion. A swivel lock member is mounted to rotate substantially about the axis of the shaft and to reciprocate together with the shaft and the knife. The swivel lock member is selectively rotatable between (1) an unlocked position at which the swivel lock member does not engage the first engageable portions and (2) a locked position at which the swivel lock member engages both of the first engageable portions to prevent the swivel lock member from movement in at least one of the back and forth directions along the axis of the shaft, thereby preventing the shaft and the knife from reciprocating movement in at least one of the back and forth directions when the swivel lock member is in the locked position and engaging the first engageable portions.
In another aspect, the invention provides a pair of second posts disposed substantially parallel to the shaft, each second post having one end mounted to the housing, and each second post has a second engageable portion. The swivel lock is rotatable to a locked position at which the engaging portions each engage one of the second engageable portions to prevent the swivel lock member from movement in at least one of the back and forth directions along the axis of the shaft, thereby preventing the shaft and the knife from reciprocating movement in one of the back and forth directions when the swivel lock is in the locked position and engaging the second engageable portions.
In still another aspect, the invention provides a method for locking a knife gate valve having a housing and a reciprocating shaft that reciprocates a knife in back and forth directions and has a pair of first posts disposed substantially parallel to the shaft, each first post having one end mounted to the housing, and each first post having a first engageable portion comprising the steps of positioning the knife in a desired position. The rotating a swivel lock member is rotated substantially about the axis of the shaft into a locked position at which the swivel lock member engages both of the first engageable portions to prevent the swivel lock member from movement in at least one of the back and forth directions along the axis of the shaft, thereby preventing the shaft and the knife from reciprocating movement in at least one of the back and forth directions when the swivel lock member is in the locked position and engaging the first engageable portions.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract included below, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.